Introduce a syntax making declared aliases optional

Details

A relation name is no longer required in the left side of a query statement. Instead, a fat arrow (=>) can be used to signify it. To refer the last relation, an arroba (@) can be used.

Description

This is something Daniel and I have talked about before, and now that we have the @ syntax, this is easy to implement. The idea is that relation names are no longer required, and you can instead use a fat arrow (obviously that can be changed) to signify this. The benefit is not having to engage in the mental load of having to name everything.

One other possibility is just making "alias =" optional. I fear that that could be a little TOO magical, but I welcome opinions.